1. Technical Field
The present disclosure relates to fluorescent lamps, and particularly to a fluorescent lamp capable of providing balanced driving electric potentials to a plurality of lamp tubes thereof.
2. Description of Related Art
Cold cathode fluorescent lamps (CCFL) are widely used in electronic displays as backlights. Referring to FIG. 3, one such CCFL driving circuit 1 generally includes a first transformer 10, a second transformer 12, a power supply 14, a converter 16, and four lamp tubes 18, 20, 22, 24. The first transformer 10 includes a first primary side 100 and a first secondary side 102. The second transformer 12 includes a second primary side 120 and a second secondary side 122. The power supply 14 is connected to the first primary side 100 and the second primary side 120. The converter 16 includes two transistors 161, 162 both connected to the first primary side 100 and the second primary side 120. The lamp tubes 18, 20 are respectively connected to two ends of the first secondary side 102. The lamp tubes 22, 24 are respectively connected to two ends of the second secondary side 122.
In use, the two transistors 160, 162 of the converter 16 are alternately turned on, such that a direct current (DC) provided by the power supply 14 periodically passes through the first primary side 100 and the second primary side 120. Thus, the DC is converted into a square wave alternating current (AC) passing through the first primary side 100 and the second primary side 120. The square wave AC generates a corresponding sine wave AC in the first secondary side 102 and the second secondary side 122, and the sine wave AC drives the lamp tubes 18, 20, 22, 24 to emit light.
For maximum light quality, in the CCFL 1, every pair of lamp tubes connected to the same transformer, such as the pair of lamp tubes 18, 20 both connected to the first transformer 10 or the pair of lamp tubes 22, 24 both connected to the second transformer 12, must be configured to exhibit identical parasitic parameters, such as capacitances, inductances, and other parameters. If any pair of lamp tubes connected to the same transformer exhibits different parameters, the light quality of the CCFL 1 may be adversely affected. For example, referring to FIG. 4, if the parasitic parameters of the lamp tubes 18, 20 are different from each other, when they are driven by the same sine wave AC provided by the first transformer 10, the sine wave AC may generate different electric potentials in the lamp tubes 18, 20. Thus, luminance among the lamp tubes 18, 20 may vary, adversely affecting light quality of the CCFL 1.
Therefore, there is room for improvement within the art.